Roadway Proximity and Risk of Sudden Cardiac Death in Women

Study Questions:

Is exposure to traffic associated with risk for sudden cardiac death (SCD)?

Methods:

Data from the Nurses’ Health Study (NHS) were used for the present analysis. The NHS is a prospective cohort study that began in 1976 with 121,701 female registered nurses, ages 30-55 years, who each completed a mailed questionnaire and provided implied informed consent. Residential distance to roadways was determined using residential addresses from 1986-2012. SCDs were confirmed by physician review of medical records and next-of-kin reports regarding the circumstances surrounding the death if not adequately documented in the medical record. Cardiac deaths were considered sudden if the death or cardiac arrest occurred within 1 hour of the onset of symptoms. Women were excluded if they had cancer, cardiovascular disease, or died prior to baseline.

Results:

A total of 107,130 women were included, of which 523 cases of SCD were identified during the follow-up period. The women were 64.3 years old on average, with an average body mass index of 26.3, were mostly white (94%), postmenopausal (86%), never (44%) or former (42%) smokers, and most (58%) exercised less than 2 hours per week. In age- and race-adjusted models, women living within 50 m of a major roadway had an elevated risk of SCD (hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.18-2.05). The association was attenuated, but still statistically significant after controlling for potential confounders and mediators (HR, 1.38; 95% CI, 1.04-1.82). The equivalent adjusted HRs for nonfatal myocardial infarction and fatal coronary heart disease (CHD) were 1.08 (95% CI, 0.96-1.23) and 1.24 (95% CI, 1.03-1.50), respectively.

Conclusions:

The investigators concluded that among this cohort of middle-aged and older women, roadway proximity was associated with an elevated and statistically significant risk of SCD and fatal CHD, even after controlling for other cardiovascular risk factors.

Perspective:

These data add further evidence of increases in cardiovascular risk related to air pollution related to traffic. Efforts to reduce such pollutants may assist in the reduction of cardiovascular events including SCD.